Hydrogenation of Substituted Benzenes Containing Nitro and Azo Groups over Skeletal Nickel in Aqueous Solutions of 2-Propanol

Russian Journal of Physical Chemistry A - An analysis is made of the kinetic characteristics of the hydrogenation of 4-nitro- and 2-nitro-2'-hydroxy-5'-methylazobenzenes, 4-nitroaniline and...     

A tunable gas sensor using an acoustic waveguide

A tunable gas sensor using surface acoustic waves (SAW) is described. It is designed on the basis of a waveguide delay line fabricated on a piezoelectric substrate made of 128° Y-cut LiNbO₃. A voltage applied between the waveguide and two electrodes causes a local change in the properties of the substrate near the waveguide and differently affects the sensor’s response to the vapors of various analytes. Some results of the experimental study of the sensor, which show the change in the selectivity under the effect of voltage, are presented. The analytes used for testing include a number of alcohols and deionized water. The possibilities for employing such a sensor in the sensor arrays of gas analyzers of the electronic nose type are discussed.     

Breaking of a weak shock wave on shallow water

A perturbation method is used to derive the fundamental equations and certain necessary and sufficient conditions for the breaking of weak shock waves encountered in the investigation of the one-dimensional and two-dimensional systems of equations of motion of shallow water.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 173, pp. 159–162, 1988.     

Convergence of the method of characteristics in approximate solution of a semilinear partial differential equation of first order

We construct an approximate solution for an initial boundary-value problem of the formu _t (x, t) + a (x, t) u_x (x, t)=b (x, t, u), u (x, 0)=u₀ (x),u (0,t)=u₁ (t) by the method of characteristics. It is proved that the approximate solution converges to the exact one with rate of convergence of second order.Translated from Ukrainskii Matematicheskii Zhurnal, Vol. 42, No. 8, pp. 1128–1138, August, 1990.